The present invention pertains to a medical tool such as a dental tool, and in particular to a disposable dental tool, made primarily from plastic and easy to assemble. The invention includes a polishing cup designed to keep polishing paste in the cup during the polishing operation. The dental tool connects to the cup to positively drive the cup, while still allowing use with ordinary polishing cups. The housing of the invention is designed to enclose a pair of gears in a manner similar to common prophy angles, and yet allows for larger sized gears by having a housing which wraps around the gears to provide protrusions at the location of the gears so that gears having a greater diameter than the diameter of the main body housing can be inserted inside.
Medical tools such as prophy angle dental tools are either disposable or non-disposable. The non-disposable tools comprise primarily metal parts which are designed for repeated use and require sterilization between uses. Due to the risk of infection and the cost of sterilizing tools after each use, disposable tools are desirable. Disposal of metal tools, however, is not economical. Consequently, plastic prophy angles have been developed which are less expensive than metal ones, and thus can be disposed of economically.
While making parts of the device from plastic reduces the cost, there are some inherent disadvantages to the use of plastic. First, deformation of the plastic is a much greater problem than it was with metal, where it was virtually nonexistent over the life of the tool. When a plastic prophy angle device is connected to a drive motor, the connecting clamp tends to deform the plastic shaft, and thus hinder or impede the operation of the instrument. Second, while the gears of the prophy angle can be made from plastic, such gears tend to wear out much more rapidly than metal gears, and are less accurate and more prone to slippage. Furthermore, plastic gears cannot transmit as much torque as metal gears.
Conventional prophy cups have a recess at one end for receiving a nub or protrusion. The prophy cup is made from an elastic material so that it can deform to accommodate the nub. In a conventional prophy angle tool, slippage can occur between the cup and the nub. To eliminate this slippage, one solution has been to provide a flange of substantially two dimensions projecting outwardly from the end of the nub, and a corresponding groove at the bottom of the recess to accommodate the flange in a manner similar to a screwdriver and a screw head. While such design will reduce the slippage, the modified nub cannot accommodate conventional prophy cups which do not have the screw head formation at the bottom of the recess.
Another problem with prophy cups is the tendency of paste in the prophy cup to migrate outward out of the cup during operation of the tool, thus splattering the patient, doctor, and their surroundings and reducing the effectiveness of the polishing.
In view of the foregoing, it is an object of the present invention to provide a disposable prophy angle dental tool which is made primarily of plastic components, yet eliminates deformation during attachment to the motor portion of the device.
Another object of the present invention is to provide a disposable prophy angle dental tool which has primarily plastic components and can be simply and easily constructed.
Another object of the present invention is to provide a prophy angle dental tool having a housing which permits the use of larger diameter gears, such as beveled gears.
Yet another object of the present invention is to provide a prophy angle dental tool which allows for the attachment of a positive drive prophy cup, but still allows for use with conventional prophy cups.
Another object of the present invention is to provide a prophy angle dental tool which has a specific rib formation on the inside of the cup to reduce the splattering of paste out of the cup during operation of the dental tool.
Yet another object of the present invention is to provide a dental tool which evenly distributes paste along the inner surface of the cup wall during operation of the dental tool.